ado@elsie.UUCP (Arthur David Olson) (05/20/85)
The usual way of doing file system backups is to identify processes using the file system, doing in all such processes, unmounting the system, and proceeding with the dump. How about being able to "freeze" file systems instead? Once a freeze system call was issued for a file system, processes that attempted to write to it would block until the appropriate "thaw" call was made. Seems to me like a cleaner solution that the "fuser" and "ofile" approaches that have been discussed. And you can avoid doing in any processes. (Question for those in the know: could such an idea be implemented using any of the file locking schemes that exist now?) -- UNIX is an AT&T Bell Laboratories trademark. Activity is the beaver's trademark. -- UUCP: ..decvax!seismo!elsie!ado ARPA: elsie!ado@seismo.ARPA DEC, VAX and Elsie are Digital Equipment and Borden trademarks
henry@utzoo.UUCP (Henry Spencer) (05/21/85)
> How about being able to "freeze" file systems instead? Once a freeze system > call was issued for a file system, processes that attempted to write to it > would block until the appropriate "thaw" call was made. One problem is that this doesn't necessarily guarantee that things like databases are in a consistent state, which will matter if you ever have to bring them back from backups. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry